14-1 What are symbiotic relationships?
Aim: What are symbiotic relationships?
OBJECTIVE: Describe the three types of symbiotic relationships.
Key Terms
symbiosis (sihm-by-OH-sihs): close relationship between different species living in close association
with each other
mutualism: relationship between two different kinds of organisms that benefits both of them
commensalism: relationship between two different kinds of organisms in which one benefits and the
other is unaffected
parasitism: relationship between two different kinds of organisms in which one lives on or in another
organism and causes it harm
host: organism a parasite feeds on
Lesson Summary
• A symbiotic relationship is a close relationship between two organisms from different species.
• A relationship between organisms that makes survival easier for both is called mutualism.
• Commensalism is a relationship between two different kinds of organisms in which one benefits and
the other is unaffected.
• Parasitism is a relationship between two different kinds of organisms in which one lives in or on the
other and causes it harm.
OBJECTIVE: Describe the three types of symbiotic relationships.
Key Terms
symbiosis (sihm-by-OH-sihs): close relationship between different species living in close association
with each other
mutualism: relationship between two different kinds of organisms that benefits both of them
commensalism: relationship between two different kinds of organisms in which one benefits and the
other is unaffected
parasitism: relationship between two different kinds of organisms in which one lives on or in another
organism and causes it harm
host: organism a parasite feeds on
Lesson Summary
• A symbiotic relationship is a close relationship between two organisms from different species.
• A relationship between organisms that makes survival easier for both is called mutualism.
• Commensalism is a relationship between two different kinds of organisms in which one benefits and
the other is unaffected.
• Parasitism is a relationship between two different kinds of organisms in which one lives in or on the
other and causes it harm.